In some helicopters, rotor blades utilize electric heating elements for ice protection. Typically, these heating elements are powered by a generator having stationary winding assemblies, and the power is transferred to the rotating mast through a slip ring. However, slip rings may increase complexity and operating costs and decrease reliability.
Mast-mounted generators are sometimes used, for example to power lights located on the rotor blades. However, because of the relatively slow rotation of the main rotor mast, mast-mounted generators are usually limited in the amount of power that can be produced.